It seems that meth-amphetamine and methcathione are drugs that are all fairly easily produced. the ingredients are easy enough to procure depending on where you live at. But all of the precursors and raw materials are kinds of things that are always going to be hard for the LEO to stop the production of.
Tweaked analogues and all the raw source precursors required i.e. PSE or EPH are easily procured, so many labs in asia are turning it out in very large amounts constantly. And it can be easily produce from natural sources.
The other chemicals require are not really going to drawn any attention unless purchased in short periods of time in large amounts. people can easily keep producing these chemicals if they have enough experience, patience and sources
~'this site has loads of anti-meth propaganda stuff still interesting
~*check the picture of the dudes loading up a few kilo drum of ephedrine LOL*